Don Terrill’s Speed-Talk

Ported t.b. and t.b. spacer. Notice the fasteners at the ends need to be installed because they thread into the plenum.

Back from a long trip with DV and some dyno experience to this project. I had two long car trips with DV and we had a discussion on this project. The customer has really done his homework and built many test fixtures, test pipes and alignment dowels to have reliable data. I recieved new info on customer specs before my DV trip. Some of this I may have discussed before some will be new.
Rpm limit, 7000rpm.
Valve sizes, aftermarket +1mm head size, stock length, 7mm stem, reduced from 8mm
Light mechanical buckets
Aftermarket valve springs
Custom vvt control customer designed
Engine must have high specific output AND tow 3000lbs.
Offset cylinder bore shift 1mm
Custom cut up stock intake manifold with sheet plenum and epoxied ram stacks fully ported with adjusted taper.
Ported stock throttlebody
Increased diameter valve seats
Welded combustion chambers to increase pressure recovery.
Custom welded exhaust tri y design low restriction muffler
Custom mechanical cam

Now the converstion with DV was very interesting due to some of the application challenges.
First was the rpm limit and towing. This takes a bunch of practical mods off the table as they just will not be worth the effort with these restrictions.
Custom welded chambers, stock chambers will be fine with minor grinding mods.
Oversized valve seats, due to casting thickness 1mm oversized valves on stock seats push casting thickness so oversized will not help.
Porting for max cfm intake and exhaust ports, less cfm traded for higher port energy will work better for towing and limited rpm while still reaching 7000rpm limit with ease through modified intake manifold. New intake and exhaust port designs are aimed at a much reduced port cc while only losing a small amout of cfm.
DV, quote, "What he really needs is to stroke it or supercharge it!"

Looking inside top of intake manifold and blending of trumpets to manny with epoxy. This was more work than you would think. The final design took the outlet size of trumpet brought right to flange and then a slight ar edge to lower intake manifold.

Much reduced size intake port. Yes, this port gives up a few cfm to the highest flowing port previously tested but Will have better port energy and torque at a lower rpm.

Same idea with new exhaust port design.

One of the many customer designed test pipes. This is 1 3/8" 90 degree tube which I feel would make the most of this combo with rpm limits.

This is a really cool project....

1 3/8" straight exhaust pipe on a older exhaust port for flow comparison.

Casper393W wrote: ↑Thu Nov 22, 2018 3:32 pm This is a really cool project....

Thanks! It is.

Offset in both ports are towards cylinder wall?
Have you tested how much it gained compared to basic port or did you go straight to offset?

Pekka

WPH wrote: ↑Fri Nov 23, 2018 3:09 am Offset in both ports are towards cylinder wall?
Have you tested how much it gained compared to basic port or did you go straight to offset?

Pekka

Ports started straighter and have developed with a twist to dump towards the center of the cylinder and accept flow from the center of the cylinder. DV calls it port biasing, it seems to work best at the higher lift points. It also helps with port airspeeds. Thanks, Charlie

Carnut1 wrote: ↑Thu Nov 22, 2018 3:22 pm 20181122_141007.jpg Much reduced size intake port. Yes, this port gives up a few cfm to the highest flowing port previously tested but Will have better port energy and torque at a lower rpm.

Just to be clear the center of the cylinder in this pic is on the left and the right is the cylinder wall

Carnut1 wrote: ↑Thu Nov 22, 2018 3:24 pm 20181122_141139.jpg Same idea with new exhaust port design.

Just to be clear in this pic the center of the cylinder is on the right and the left is the cylinder wall.

WPH wrote: ↑Fri Nov 23, 2018 3:09 am Offset in both ports are towards cylinder wall?
Have you tested how much it gained compared to basic port or did you go straight to offset?

Pekka

At 3:30 am this quote got me thinking..... The bias I used was similar to what works on a sbc. I have more junk ports that I am thinking of biasing more like an ls3. I am working on my second ls3 project and they flat work! Pekka thanks for the sleepless night, might as well make coffee.

Different view of trumpet to top manny transition. There are a few epoxy inclusions so this will need a final epoxy coat after I get each one as close to the same as possible. The lower intake flows on the same intake port are very close which I am happy about. Thanks, Charlie